In an analog phased array radio-frequency (RF) front-end, each antenna may receive and transmit two orthogonally polarized electromagnetic waves. Switches and/or filters may provide channel or beam selectivity and can be implemented in RF micro-electromechanical systems (MEMS) technology for reduced insertion loss (e.g. best noise figure). An amplification stage may be followed by fundamental elements of analog beam-forming, such as phase shifters or time delay units, variable attenuators, and summing circuits. Controlling amplitude and phase shift (or time delay for very large aperture or very wideband arrays) of each channel may implement a coherent weighted sum used to electronically reconfigure the far-field radiation pattern (e.g., to form beams or place nulls). As the size of the aperture and the number of antennas increases, beamwidth may narrow and directivity may increase.
To reduce overall system cost, many of the components can be consolidated into integrated circuits or multi-chip modules and collocated on a multilayer printed circuit board. Further reduction in system cost can be achieved through the utilization of lowest-cost technology nodes and processes, such as silicon-germanium (SiGe), for consolidation of beam-forming elements. Higher component consolidation allows for reduction in unit cell size, and consequently, extension of scan volume for a fixed maximum operational frequency, or extension of maximum operational frequency for a fixed scan volume. Recent advancements in the state-of-the-art for phased arrays include multiple unit-cell multilayer antennas integrated into subarrays by stacking up the same multilayer antennas. Such phased arrays have achieved up to 30% bandwidth, up to 30 degrees conical scan volume, and thicknesses on the order of one inch, in designs that can be instantiated from S- to X-bands. Some applications may require a wider bandwidth and closer spacing, which may typically lead to large profile antennas that no longer can maintain a low-profile feature. Therefore, the need exists for a wideband antenna unit cell design for wide-scan, low-profile, and low-cost phased arrays.